#include <stdio.h>
#include <math.h>
double T,N[50],X[50][50],Y[50][50];

int main(int argc, char *argv[]) 
{
	double S(int m);
	scanf("%lf",&T);
	for(int i=0;i<T;i++)
	{
		scanf("%lf",&N[i]);
		
		for(int j=0;j<N[i];j++)
			scanf("%lf%lf",&X[i][j],&Y[i][j]);
		printf("%.1lf\n",S(i));
	}
	
}
double S(int m)
{
	double max,n;
	n=0.5*((X[m][0]-X[m][2])*(Y[m][1]-Y[m][2])-(X[m][1]-X[m][2])*(Y[m][0]-Y[m][2]));
	max=n>=0?n:-n;
	for(int a=0;a<N[m];a++)
		for(int b=a+1;b<N[m];b++)
			for(int c=b+1;c<N[m];c++)
	{
		n=0.5*((X[m][a]-X[m][c])*(Y[m][b]-Y[m][c])-(X[m][b]-X[m][c])*(Y[m][a]-Y[m][c]));
		n=n>0?n:-n;
		if(max<n)max=n;
	}
	return max;
}